Center-jig.



PATENTBD APR. 25, 1905.

E. A. CHRISTOPH,

CENTER JIG. APPLIOATION FILED APB. 21, 1904.v

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bufera@ v E W PATENTED APR. 25, 1905.

E. A. CHRISTOPH.

GENTER JIG.

APPLIOATION FILED APB.. 21. 1904.

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UNTTED STATES Patented April 25, 1905.

EMIL A. CHRISTOPH, OF CHICAGO, ILLINOIS.

CENTER-JIG.

SPECIFICATION forming part of Letters Patent No. 787,893, dated April25, 1905.

Application filed April 21, 1904. Serial No. 204,248.

To 10H 07mm if 11m/y concern.;

Bc it known that I, EMIL A. CimrsTorH, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Center-Jigs, of whichthe following is a specification.

The object of this invention is to provide a simple and convenientcenter-jig Vfor automatically centering rods, bars, and other work .fordrilling.

In the accompanying drawings, illustrating the preferred embodiment ofthe invention, Figure l is a plan view of the invention, showing thejaws partly opened and a portion of one jaw broken away. Fig. 2 is asectional view showing a round bar in the jig. Fig. 8 is a similar viewshowing a square bar in the jig. Fig. 4 shows another constructionembodying two guide-rods.

Referring' to the drawings, lO and 11 designate two jaws, one of which,as l0, is slotted at l2 between its ends to receive the other jaw. Thesejaws are preferably formed with sockets I3 of right-angle shape, so thatthey will securely hold and center round bars 14,

as well as square bars l5 and other work of i threaded portion Q5 of thescrew-rod by the g nuts Q6 and lock-nuts QT. This arm is provided with adrill-guide opening QS to receive the drill and hold it at a pointcentrally of the clamping-jaws, and a sleeve 30,0f steel or othersuitable material, is preferably secured in said The free end of openingto prevent wear.

the arm rests upon the guide-rod 16.

As the screw-rod acts as a guide for the jaws, l have found that the jigconstructed l with a single guide-rod, as shown in Fig. l,

will work very satisfactorily; but, if desired, an additional guide-rod16 maybe secured in a lug I7 on one of the jaws, as l0, andthe other jawprovided with a tubular lug 18' and sleeve I9/ to receive said rod, theobject of this additional guide-rod being simply to increase thestrength and stability of the device.

In practice, the arm having' first been set to bring the drill-guideopening central of the jaws, the work is arranged in place between thejaws and the screw-rod is operated to clamp the jaws thereon. The workclamped in the jig is then arranged on the table of a drilling-machineand the drill 29 inserted in the guide-opening 28.

This device automatically centers the work without necessitatingcalculation or adjustments, and thus greatly simplifies and reduces thework of the machinist. Furthermore, it acts as a guide for the drill andcauses it to operate properly on the work.

Vithout limiting myself to the exact construction and arrangement ofparts herein shown and described, what I claim, and desire to secure byLetters Patent, isvl. In a device of the character described, a pair ofjaws, a guide for the jaws, a screwrod for clamping the jaws upon thework, and a drill-guide pivotally mounted on said screwrod.

2. In a device of the character described, a guide-rod, a screw-rod, apair of jaws on said rods, and a drill-guide pivotall y mounted on thescrew-rod and arranged to rest upon the guide-rod.

3. Ina device of the character described, a guide-rod and a screw-rod, apair of jaws carried by said rods, and an arm pivotal] y mounted on thescrew-rod and arranged to rest upon the guide-rod and provided with adrill-guide opening located centrally of the jaws.

-L In a device of the character described, a guide-red and areversely-threaded screwrod, a pair of jaws carried by said rods, saidscrew-rod being unthrcadcd at or about its of said jaws being slottedlengthwise between its ends to receive the other jaw, and a drillguidepivotally mounted on the screw-rod.'

EMIL A. CHRISTOPH.

Witnesses:

WALTER J. GENDER, WM. O. BELT.

